Stubborn stains on solar panels—like bird droppings, tree sap, and hard water spots—are common in San Jose, especially in neighborhoods with heavy tree coverage or construction dust. These stains can’t be rinsed away by rain or removed with basic water alone. That’s why professional solar cleaners in San Jose use deionized water combined with solar-safe, non-abrasive brushes to lift g... https://g.co/kgs/YGiVfxV